As global demand on hydrocarbon reserves has continued to increase, more efficient utilization of petroleum and gas reserves has become an important complementary strategy to the development and deployment of sustainable energy generation. Olefin production is critical for the polymer and chemical industries and is widely utilized as intermediates in the production of transportation fuels. Historically, olefin production has generally been accomplished by one of three processes: thermal cracking of alkanes at high temperatures and catalytic dehydrogenation with Pt nano-particle or Cr oxide catalyst technologies at temperatures above about 600° C. where equilibrium favors high olefin yields; or fluid catalytic cracking. For ethylene thermal cracking of ethane, LPG and heavier feedstocks continue to be the primary route. Thermal cracking of LPG or heavier feedstocks also provide significant quantities of prophylene byproduct. Fluid catalytic cracking in refineries also produce significant quantities of propylene byproduct. However, over the past two decades, propylene growth rate has outpaced these conventional supply routes leading to construction of a number of commercial units for selective catalytic dehydrogenation of propane to propylene.
For alkanes with three or more carbons, thermal cracking results in mixtures of C—C and C—H cracked products. Propane, for example, produces propylene, ethylene, hydrogen, and methane. Because of the low olefin yields by thermal cracking, however, catalytic conversion processes are often favored. While propylene selectivity is higher for catalytic dehydrogenation of propane than thermal cracking, increasing the propylene selectivity, i.e., reducing the C—C cleavage reaction in favor of the dehydrogenation, remains an important catalytic goal. With catalytic dehydrogenation, there is also deposition of carbon on the catalyst surface leading to rapid loss of activity, often in a few hours, thus requiring frequent regeneration, by combustion of the carbon, or coke, and expensive process designs.
Therefore, there remains a need for catalysts with high selectivity in the conversion of alkanes to alkenes, and that are additionally long-lived with minimal decrease in activity over time.